so they can blink
camel
The purpose of people wanting to get double eyelids due to the fact they want to look like the rest of the people. Usually, it's Asians that don't have double eyelids. Some do it to look cute, others do it to build up self-esteem.
Fish don't have eyelids because they have evolved to protect their eyes using a transparent layer of tissue called the cornea. This tissue keeps their eyes moist and helps maintain their vision underwater. Eyelids would hinder their ability to see and navigate effectively in their aquatic environment.
The main purpose of eyelids is to moisten the surface of the eye, which in terrestrial vertebrates (like you and I) is nessesary to provide the eye with lubrication to move. Underwater, the eye is lubricated by the water, and kept moist without effort, thus the eyelids are not present because they don't need to be there. Interestingly, although it may seem that eyelids are the norm, the majority of species with eyes don't have eyelids. Insects for example.
Eyelids and their lashes protect the eye from damage from the weather, hazards like insects as well as airborne particles of dust and germs. Additionally they are ornamental providing a defined frame to the eye.
A salamander is a amphibian.
it is a Amphibian... A frog is an amphibian, not a reptile.
no they dont have eyelids
Dogs actually have 3 eyelids.
3 eyelids
Yes, dinosaurs did have eyelids.